I feel like not having dedicated shed/storage area in the house plan is one of most common architectural mistakes, given just how often garage ends up being just that
On the other hand, I've often thought of adding a shed and it would invariably end up being a case of crap expanding to fill the space allotted to it. I don't need another 10'x13' shed to store more stuff. (I admittedly already have a workshop that sticks off the side of the garage.)
Right but separate room at least gives you a barrier. "This is place for crap, this is place for car".
And if you have house with any kind of garden, you will need a place to store some basic tools, and maybe a grill, if house doesn't come with that it will naturally clog the garage.
